Light guide plate structure and back light module

ABSTRACT

A structure of a light guide plate comprising a light guide plate and a plurality of transparent elements is disclosed. The light guide plate comprises at least onelight incident surface, a light scattering surface and a light emitting surface. The light scattering surface has a plurality of notches and these transparent elements are disposed therein. The transparent elements refractive index is different from that of the light guide plate. By disposing these transparent elements, the light scattering surface can improve light scattering effect. In addition, a back light module comprising a linearlight source and a light guide plate structure mentioned above is also disclosed. The linearlight source is disposed next to the light incident surface of the light guide plate.

BACKGROUND OF INVENTION

1. Field of the Invention

The present invention relates to a light guide plate structure and aback light module, and more particularly to a light guide platestructure for improving scattering effects on a light scattering surfaceand a back light module applied therefrom.

2. Description of the Related Art

For the trend of small sizes of electronic products, the development ofelectronic devices is toward high density and integrity in small sizeelectronic products. Because a variety of functions embodied withinelectronic products with small sizes, a large number of portable deviceshave been popularly used and replaced the big sized electronic products.Therefore, they have become the main stream in consumer market. Theseportable devices includes, such as notebooks, cell phones, electronicdictionaries, personal digital assistants, web pads, tablet PC andportable games.

For the application of small size electronic products, liquid crystaldisplays (LCD) with high efficiency of space, high quality, low powerconsumption and low or no radiation have been popularly used. LCD iscomposed of a liquid crystal panel and a back light module. Becauseliquid crystal within the panel does not illuminate itself, the backlight modules must provide a plate light source for the panel. Then, LCDserves the function of display. Therefore, back light modules are veryimportant in displays.

FIG. 1 is a cross-sectional schematic drawing showing a prior art backlight module. Referring to FIG. 1, the back light module 100 includes alight guide plate 110, a liner light source 120 and a reflective cover130. The light guide plate 110 is, for example, a plate-type light guideplate, which comprises at least one light incident surface 112, a lightscattering surface 114 and a light emitting surface 116. The lightincident surface 112 is on a sidewall of the light guide plate 110, thelight scattering surface 114 is on a bottom surface of the light guideplate 110 and the light emitting surface 116 is on a top surface of thelight guide plate 110.

The liner light source 120 is, for example, a cold cathode florescentlamp, which is disposed next to the light incident surface 112 of thelight guide plate 110, wherein light from the liner light source 120transmits through the light incident surface 112 and enters into thelight guide plate 110, and the light scattering surface 114 passes thelight to the light emitting surfaces 116 and out thereof.

Additionally, the reflective cover 130 is disposed next to the lightincident surface 112 of the light guide plate 110 and covers the linerlight source 120 for reflecting light from the liner light source 120 tothe light incident surface 112 of the light guide plate 110.

Referring to FIG. 1, the light scattering surface 114 of the light guideplate 110 provides a enough scattering area. Therefore, light from theliner light source 120 after being scattered on the light scatteringsurface 114 can uniformly travel to the light emitting surface 116, andthe light exiting form the light emitting surface 116 transforms into aplate light source. It should be noted that a plurality of transparentbumps 140 are disposed on the light scattering surface 114 as scatteringspots thereof in prior art. The transparent bumps 140, however, are madeof the same material of the light guide plate 110 and have the samerefractive index as the light guide plate 110. Therefore, the scatteringeffect on the light scattering surface is limited.

FIG. 2 is a cross-sectional schematic drawing showing a prior art backlight module. Referring to FIG. 2, a back light module 100′ has the samestructure as the back light module 100 described in FIG. 1. The samedescriptions will not be repeated herein. The difference between thesetwo back light modules is that a plurality of holes 150 are formed onthe light scattering surface 114′ serving as scattering spots thereon.However, in the prior art back light module light still transports inthe same material. Therefore, the scattering effect on the lightscattering surface 114′ is limited.

From the descriptions mentioned, the prior art back light module byforming either transparent bumps or holes on the light scatteringsurface of the light guide plate cannot provide excellent scatteringeffect and a uniform plate light source because of back scatteringeffects thereon.

SUMMARY OF INVENTION

In an embodiment of the present invention, a of a light guide platestructure, having a plurality of notches on a light scattering surfaceand disposing a plurality of transparent elements therein, is providedto improve the scattering effect thereof, wherein the refractive indexof the plurality of transparent elements is different form that of theplurality of the light guide plate.

In an embodiment of the present invention, a back light module isprovided to generate a better scattering effect on a scattering lightsurface and a plurality of notches are formed on the light scatteringsurface of the light guide plate and a plurality of transparent elementsare disposed therein to provide a more uniform plate light source,wherein the refractive index of the plurality of transparent isdifferent form that of the plurality of the light guide plate.

Accordingly, the present invention provides a light guide platestructure applied to a back light module and adapted to transform aliner light source into a plate light source. The guide light sourcestructure comprises a light guide plate and a plurality of transparentelements. The light guide plate comprises at least one light incidentsurface, light scattering surface and a light emitting surface. Thelight incident surface is on a sidewall of the light guide plate, thelight scattering surface is on a bottom surface of the light guide plateand the light emitting surface is on a top surface of the light guideplate, wherein the light scattering surface has a plurality of notches.The plurality of transparent elements are disposed within the pluralityof notches and a reflective index of the plurality of transparentelements is different from that of the light guide plate.

The present invention provides a back light module adapted to provide aplate light source. The back light module comprises a light guide platestructure and a liner light source. The guide light source structurecomprises a light guide plate and a plurality of transparent elements.The light guide plate comprises at least one light incident surface,light scattering surface and a light emitting surface. The lightincident surface is on a sidewall of the light guide plate, the lightscattering surface is on a bottom surface of the light guide plate andthe light emitting surface is on a top surface of the light guide plate,wherein the light scattering surface has a plurality of notches. Theplurality of transparent elements is disposed within the plurality ofnotches and a reflective index of the plurality of transparent elementsis different from that of the light guide plate. The liner light sourceis next to the light incident surface of the light guide plate, whereinlight from the liner light source transports the light incident surfaceand enters into the light guide plate, and the light scattering surfacepasses the light to the light emitting surfaces and out thereof.

In preferred embodiments of the present invention, these transparentelements are made of transparent material, such as glass or acrylic. Inaddition, the light guide plate is a plate-type light guide plate or amesa light guide plate. When the light plate is a mesa light guideplate, the plurality of transparent elements have different sizes, theplurality of transparent elements are disposed on the light scatteringsurface in sequence by the size thereof, and bottom surfaces of theplurality of transparent elements are substantially on a same surface.Therefore, the mesa light guide plate can be firmly disposed on aplastic frame. Moreover, the liner light source is, for example, a coldcathode florescent lamp.

In preferred embodiments of the present invention, the back light modulefurther comprises a reflective cover, which is disposed next to thelight incident surface of the light guide plate and covers the linerlight source for reflecting light from the liner light source to thelight incident surface of the light guide plate. In order to improveluminance of the back light module, a diffusion sheet and a brightnessenhancement film can be applied thereto. In the embodiment, thediffusion sheet can be disposed, for example, on the light emittingsurface of the light guide plate, and the brightness enhancement filmcan be disposed on the diffusion sheet.

In the present invention, the plurality of notches are formed on thelight scattering surface of the light guide plate and the plurality oftransparent elements are disposed within the notches. In addition, therefractive index of these transparent elements is different from that ofthe light guide plate. When light comes into and goes out thesetransparent elements through the light guide plate, a better scatteringeffect is achieved and the back light module of the present inventionprovides a more uniform plate light source because of the refractiveindex difference between these transparent elements and the light guideplate.

In order to make the aforementioned and other objects, features andadvantages of the present invention understandable, a preferredembodiment accompanied with figures is described in detail below.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross-sectional schematic drawing showing a prior art backlight module.

FIG. 2 is a cross-sectional schematic drawing showing a prior art backlight module.

FIG. 3 is a cross-sectional schematic drawing showing a first preferredback light module in accordance with the present invention.

FIG. 4 is a cross-sectional schematic drawing showing a second preferredback light module in accordance with the present invention.

DETAILED DESCRIPTION

FIG. 3 is a cross-sectional schematic drawing showing a first preferredback light module in accordance with the present invention. Pleasereferring to FIG. 3, the back light module 200 comprises a light guideplate structure 300 and a liner light source 210. The light guide platestructure 300 is composed of a light guide plate 310 and a plurality oftransparent elements 312. The light guide plate 310 is, for example, aplate-type light guide plate, which comprises at least one lightincident surface 312, light scattering surface 314 and light emittingsurface 316. The light incident surface 312 is on a sidewall of thelight guide plate 310, the light scattering surface 314 is on a bottomsurface of the light guide plate 310 and the light emitting surface 316is on a top surface of the light guide plate 310, wherein the lightscattering surface 314 has a plurality of notches 318.

The plurality of transparent elements 320 are made of transparentmaterial, such as glass or acrylic, which are separately disposed withinthe plurality of notches 318 as scattering spots of the light scatteringsurface 314. Moreover, a reflective index of the plurality oftransparent elements 320 is different from that of the light guide plate310.

The liner light source 210 is, for example, a cold cathode florescentlamp, which is disposed next to the light incident surface 312 of thelight guide plate 310, wherein light from the liner light source 210transmits through the light incident surface 312 and enters into thelight guide plate 310, and the light scattering surface 314 passes thelight to the light emitting surfaces 316 and out thereof.

In addition, the back light module 200 further comprises a reflectivecover 220, which is disposed next to the light incident surface 312 ofthe light guide plate 310 and covers the liner light source 210 forreflecting light from the liner light source to the light incidentsurface 312 of the light guide plate 310. In order to improve luminanceof the back light module 200, a diffusion sheet 230 and a brightnessenhancement film 240 can be applied thereto. In the embodiment, thediffusion sheet 230 can be disposed, for example, on the light emittingsurface 316 of the light guide plate 310, and the brightness enhancementfilm 240 can be disposed on the diffusion sheet 230.

It is to be noted that the plurality of notches 318 are formed on thelight scattering surface 314 of the light guide plate 310 and theplurality of transparent elements 320 are disposed within the notches318. In addition, the refractive index of these transparent elements 320is different that of the light guide plate 310. When light comes intoand goes out these transparent elements 320 through the light guideplate 310, a better scattering effect is achieved and the back lightmodule 200 of the present invention provides a more uniform plate lightsource because of the refractive index difference between thesetransparent elements 320 and the light guide plate 310.

FIG. 4 is a cross-sectional schematic drawing showing a second preferredback light module in accordance with the present invention. A back lightmodule 200′ has the same structure as the back light module 200described in the first preferred embodiment. The same descriptions willnot be repeated. The difference between the first and the secondembodiments is that the light guide plate 310′ is, for example, a mesalight guide plate. The plurality of transparent elements 320′ havedifferent sizes, the plurality of transparent elements 320′ are disposedinto the notches 318′ on the light scattering surface 314′ in sequenceby the size thereof, and bottom surfaces of the plurality of transparentelements 320′ are substantially on a same surface. Therefore, the mesalight guide plate can be firmly disposed on a plastic frame (not shown)for improving the convenience of assembling the back light module.

From the descriptions mentioned above, in the present invention theplurality of notches are formed on the light scattering surface of thelight guide plate and the plurality of transparent elements are disposedwithin the notches for serving as scattering spots on the lightscattering surface. In addition, the refractive index of thesetransparent elements is different that of the light guide plate. Whenlight comes into and goes out these transparent elements through thelight guide plate, a better scattering effect is achieved and the backlight module of the present invention provides a more uniform platelight source because of the refractive index difference between thesetransparent elements and the light guide plate.

Although the present invention has been described in terms of exemplaryembodiments, it is not limited thereto. Rather, the appended claimsshould be constructed broadly to include other variants and embodimentsof the invention which may be made by those skilled in the field of thisart without departing from the scope and range of equivalents of theinvention.

1-6. (canceled)
 7. An apparatus, comprising: a light guide plate, saidlight guide plate comprising at least one light incident surface, alight scattering surface and a light emitting surface, wherein the lightincident surface is on a sidewall of the light guide plate, the lightscattering surface is on a bottom surface of the light guide plate, andthe light emitting surface is on a top surface of the light guide plate,wherein the light scattering surface has one or more notches; and one ormore transparent element structures, said one or more transparentelement structures disposed at least partially within the one or more ofnotches of the light guide plate, wherein a reflective index of the oneor more transparent element structures is different from that of thelight guide plate.
 8. The apparatus of claim 7, wherein said one or moretransparent element structures are disposed partially within the lightguide plate.
 9. The apparatus of claim 7, wherein the one or moretransparent element structures comprise two or more transparent elementstructures comprising different sizes.
 10. The apparatus of claim 7,wherein the one or more transparent element structures comprise two ormore transparent element structures comprising different sizes, the twoor more transparent element structures being disposed at least partiallywithin the light guide plate at least partially in sequence by size, andwherein bottom surfaces of the two or more transparent elementstructures are substantially coplanar.
 11. The apparatus of claim 7,wherein the one or more transparent element structures comprise a glassmaterial or an acrylic material.
 12. The apparatus of claim 7, furthercomprising a brightness enhancement film positioned adjacent the topsurface of the light guide plate, the brightness enhancement filmcapable of modifying luminance of the light guide plate.
 13. Theapparatus of claim 7, further comprising a diffusion sheet positionedadjacent the top surface of the light guide plate, the diffusion sheetcapable of modifying luminance of the light guide plate.
 14. Theapparatus of claim 7, further comprising a linear light sourcepositioned next to the light incident surface of the light guide plate.15. A method, comprising: reflecting light off of a light scatteringsurface of a light guide plate; and reflecting light off of one or moretransparent element structures disposed at least partially within one ormore notches of the light guide plate at a refractive index differentfrom that of the light guide plate.
 16. The method of claim 15, whereinsaid reflecting light off of one or more transparent element structurescomprises reflecting light off of one or more transparent elementstructures disposed partially within the light guide plate at arefractive index different from that of the light guide plate.
 17. Themethod of claim 15, wherein said reflecting light off of one or moretransparent element structures comprises reflecting light off of two ormore transparent element structures of different sizes disposed at leastpartially within the light guide plate at a refractive index differentfrom that of the light guide plate.
 18. The method of claim 15, whereinthe one or more transparent element structures comprise a glass materialor an acrylic material.
 19. The method of claim 15, further comprisingmodifying luminance brightness of light exiting a light emitting surfaceof the light guide plate.
 20. The method of claim 15, further comprisingmodifying luminance diffusion of light exiting a light emitting surfaceof the light guide plate.
 21. The method of claim 15, further comprisingtransmitting light into a light incident surface of the light guideplate.
 22. An apparatus comprising: a light guide plate, said lightguide plate comprising at least one light incident surface, a lightscattering surface and a light emitting surface, wherein the lightincident surface is on a sidewall of the light guide plate, the lightscattering surface is on a bottom surface of the light guide plate, andthe light emitting surface is on a top surface of the light guide plate,wherein the light scattering surface has one or more notches; and meansfor scattering light through the one or more notches of the light guideplate at a refractive index different from that of the light guideplate.
 23. The apparatus of claim 22, wherein the means for scatteringlight are disposed at least partially within the light guide plate. 24.The apparatus of claim 22, wherein the means for scattering light aredisposed partially within the light guide plate.
 25. The apparatus ofclaim 22, wherein the means for scattering light comprises a first meansfor scattering light and a second means for scattering light, whereinthe first means for scattering light and a second means for scatteringlight comprising different sizes.
 26. A system, comprising: a lightguide plate, said light guide plate comprising at least one lightincident surface, a light scattering surface and a light emittingsurface, wherein the light incident surface is on a sidewall of thelight guide plate, the light scattering surface is on a bottom surfaceof the light guide plate, and the light emitting surface is on a topsurface of the light guide plate, wherein the light scattering surfacehas one or more notches; one or more transparent element structures,said one or more transparent element structures disposed at leastpartially within the one or more notches of the light guide plate,wherein a reflective index of the one or more transparent elementstructures is different from that of the light guide plate; a brightnessenhancement film positioned adjacent the top surface of the light guideplate, the brightness enhancement film capable of modifying luminance ofthe light guide plate; a diffusion sheet positioned adjacent the topsurface of the light guide plate, the diffusion sheet capable ofmodifying luminance of the light guide plate; and a linear light sourcepositioned next to the light incident surface of the light guide plate.27. The system of claim 26, wherein said one or more transparent elementstructures are disposed partially within the light guide plate.
 28. Thesystem of claim 26, wherein the one or more transparent elementstructures comprise two or more transparent element structurescomprising different sizes.
 29. The system of claim 26, wherein the oneor more transparent element structures comprise two or more transparentelement structures comprising different sizes, the two or moretransparent element structures being disposed at least partially withinthe light guide plate at least partially in sequence by size, andwherein bottom surfaces of the two or more transparent elementstructures are substantially coplanar.
 30. The system of claim 26,wherein the one or more transparent element structures comprise a glassmaterial or an acrylic material.